WO2015140134A2

WO2015140134A2 - Laminate, pressing means, and method for the production thereof

Info

Publication number: WO2015140134A2
Application number: PCT/EP2015/055496
Authority: WO
Inventors: Andreas Arthold
Original assignee: Fritz Egger Gmbh & Co. Og
Priority date: 2014-03-18
Filing date: 2015-03-17
Publication date: 2015-09-24
Also published as: PT3119607T; EP3119607B1; WO2015140134A3; ES2668520T3; DE102014104754A1; EP3119607A2; PL3119607T3

Abstract

The invention relates to a laminate for application onto a carrier material, in particular onto a carrier plate, having a resin-impregnated decorative layer (4), and having at least one resin-impregnated core layer (6, 8, 10), wherein the decorative layer (4) and the at least one core layer (6, 8, 10) are suited to be pressed together under high pressure and heat. The technical problem addressed by the invention is that of improving a laminate for application onto a carrier material, in particular onto a carrier plate. This problem is solved in that the layer arranged opposite the decorative layer has an embossed structure substantially corresponding to a structure produced by way of grinding. The invention further relates to a pressing means, and to a method for producing such a laminate.

Description

Laminate, pressing means and process for its preparation

The invention relates to a laminate for application to a carrier material, in particular to a carrier plate, with a resin-impregnated decorative layer and with at least one resin-impregnated core layer, wherein the decorative layer and the at least one core layer are suitable to be pressed together under high pressure and heat. The invention also relates to a pressing means and a method for producing a laminate. Laminates known from the prior art are a versatile material that is processed into so-called composite elements in combination with wood-based materials or other carrier materials. The applications are diverse and require the use of different laminate qualities, which are to be adapted to the later fields of application. Classic applications or

Areas of use are e.g. Kitchen industry, door industry, office furniture industry, trade fair construction, shopfitting, decorative interior design, flooring, shipbuilding and

Vehicle construction.

The laminates are decorative laminates based on curable resins. They are multi-layered and consist, for example, at least one

melamine resin impregnated decorative paper as a decorative layer and one or more impregnated with phenolic resin kraft papers as core layers, which are pressed together under high pressure and heat. The laminate structure, resin and paper qualities, surface structures, the use of special overlays (protective layers) as well as the pressing parameters in the production decide on the laminate quality and thus on the subsequent application or the

Operation area. The decorative side of the laminate, the decorative layer may consist of decorative paper that is printed as a wood decor or Fantasy decor, or uni or white decors, which are formed, for example, as plastic layers. The

Basis weights of the decorative papers are generally between 50 and 160 g / m ² .

An essential component of laminates may be core papers, eg.

Natron kraft papers, which are also referred to as core layers or core layers. The basis weight of the core papers or Natronkraftpapiere is in the range of 70 - 300 g / m ² , with high grammages predominantly for

Compact disks are used.

An overlay is a bleached, transparent paper with a high

Resin absorption capacity and is used to protect the decoration, in particular the

Printed image of printed decor papers and to improve the

Abrasion resistance used.

An underlay or barrier paper is a paper layer between decorative and core paper or soda kraft paper, which is used to prevent chemical interference between the resins or to achieve optical effects.

Melamine-formaldehyde resins give transparent and hard coatings and are therefore ideally suited as a surface layer of decorative laminates. For the impregnation of the core layers, not least for reasons of cost, relatively elastic phenol-formaldehyde resins are used.

Decorative laminates can therefore consist of cellulose fiber webs or paper impregnated with thermosetting resins. Other natural or artificial materials can also be used as a substrate for the resin. Thus, laminates of resin-impregnated glass fiber webs are also known. The layers, preferably the paper layers with the

Manufacturing method described below with each other to the laminate connected. The supply of heat and pressure causes a flow and subsequent curing of the resins. The crosslinking of the resins, preferably reinforced by the cellulose fibers of the papers, results in a very dense material with a closed surface. In this case, individual layers of paper, even an outer layer of paper, can be uncemented prior to pressing, since during the compression of the resin also previously non-resinous layers penetrate.

At the beginning of the process, the layers of the layer structure are superimposed and then brought between two pressing means in the form of press plates or press belts. These pressing means are heated to a predetermined temperature, so that not only a sufficient pressure but also the required temperature is applied to the layers during the pressing process. The high-pressure process is thus through the simultaneous application of heat

[Temperature> 120 ° C] and a high pressure (> 25 bar) are determined so that the thermosetting resins flow and then cure to a homogeneous, non-porous material with increased density (> 1.35 g / cm ³ ) and the required Surface texture.

The aforementioned pressing means generally have a very smooth surface in order to achieve a correspondingly smooth and thus glossy surface of the laminate. It is also known that fitting on the side of the decorative layer

To provide pressing means with a macroscopic structure to achieve a visible, possibly synchronous with the decor surface texture on the decor. This, together with the decor, leads to an improved near-natural surface appearance.

The manufacturing processes are CPL processes, CPL stands for Continuous Pressed Laminates, and HPL processes, HPL is the abbreviation for High Pressure Laminates. CPL is produced in continuous double belt presses with a pressure between 25 and 50 bar and temperatures between 150 ° C and 170 ° C. Depending on the thickness of the laminate and the press zone length, this varies

Feed rate between 8 and 30 m / min.

HPL is produced in batch presses or multi-day presses with a pressure of between 70 and 80 bar and temperatures of over 120 ° C. The floor presses can have up to 45 storeys and each floor is filled with up to 24 layers of laminate (thickness approx. 0.50 to 1.90 mm). Depending on the press feed and the maximum temperature, the complete process takes

Press cycle including optional recooling for about 100 minutes.

The length and width formatting of HPL is done in separate

Steps. CPL, on the other hand, can be cut both directly in width and / or length-formatted or roll-wound directly after the press.

Laminates are understood to mean decorative laminates which

can meet different requirements. For example, there are laminates in standard quality, postformable decorative laminates, which at higher

Temperatures can also be formed, or decorative laminates with improved fire behavior.

After the laminate has been produced, it is bonded to a carrier material or a carrier plate, usually in a separate process step and with a time delay. In order to bond laminates better with a carrier plate, the backs are ground. The cut becomes one

Surface structure created, which is well wettable. A disadvantage of grinding the back, however, is that the laminate is characterized asymmetrical and tends to buckle. Therefore, quite extensive storage and

Manipulation measures and special precautions are taken.

In addition, the processing is considerably more difficult. In addition, the grinding leads to an at least partial, preferably almost complete ablation of the uppermost resin layer, so that the paper layer arranged underneath is at least partially exposed. The surface tension is thus reduced and the wettability of the surface changes. Moisture can therefore penetrate the laminate during storage before the adhesive can be applied shortly before processing. In addition, the adhesive may at least partially penetrate too deeply into the layer structure, so that more glue than necessary must be used for bonding to the carrier plate.

The present invention is therefore based on the technical problem of a laminate for application to a substrate, in particular to a

Support plate, a pressing means and a method for producing a laminate in such a way and further develop that the aforementioned disadvantages are eliminated.

The above-indicated technical problem is solved according to the invention by a laminate in which the layer arranged opposite the decorative layer is provided with an embossed structure which essentially corresponds to a structure produced by grinding.

This achieves a surface which, like a ground surface, can be well bonded without the surface being mechanically abraded, resulting in an irregular surface or asymmetry of the layer structure. Under a structure that is essentially a through

In the context of this invention, it is understood a structure whose dimensions are comparable to the dimensions of a structure produced by mechanical grinding. By impressing the structure during the production of the laminate, the uppermost resin layer is modulated and remains as a continuous and thus sealing Layer, so that despite the introduction of the structure in the surface during a subsequent storage no moisture can penetrate into the laminate. The necessary for the processing of the laminate adhesive can therefore be applied in a smaller amount, as in an above

described surface with low surface tension. In this case, no loss of quality during processing must be accepted during the gluing on the carrier plate.

As a measure and thus as a distinguishing feature of the nature of the surface of the laminate according to the invention over a ground laminate, the wettability can be used. The wettability depends on the surface tension of the surface, as a measure of the so-called

Contact angle can be measured. The size of the contact angle between liquid and surface depends on the interaction between the liquid and the surface at the interface. The smaller this interaction, the larger the contact angle becomes. From the determination of the contact angle, a measure of the wettability can thus be determined.

Actually ground surfaces, as described above as prior art, have a low surface tension and thus a good

Wettability on. When applying a tap water drop at room temperature with a maximum diameter of 15 mm, the contact angle assumes a low value in the range of less than 20 ° or less than 10 °. At a

Surface of the invention is the contact angle of the same

Drop of water above 40 °, in particular above 50 °. To carry out the measurement of the contact angle and to characterize the specific

Properties of tap water are referred to the specific description.

Another distinguishing feature between an inventive

Laminate with an embossed structure and an actually ground

Laminate surface is whether and how much water in through the surface penetrates into the laminate. In the case of a surface according to the invention, a water droplet rolls off and the water does not or only imperceptibly penetrate into the laminate, because the uppermost resinated layer has an embossed structure, so that the resinated layer as such with structure remains intact. In a ground surface of a laminate whose outer layer consists of a resin-impregnated but inherently water-absorbing material, such as paper, the water of the overlying water droplet penetrates through the ground surface into the laminate. Because the grinding of the surface, the continuous resin layer is injured and partially removed completely, so that the water-absorbing layer is exposed. In the area around the

Drops of water around this create highly visible wet areas of the water

Laminate.

In a preferred embodiment of the laminate according to the invention, the embossed structure corresponds in depth and / or geometry to a structure produced by grinding, the depth of the embossed structure preferably having an average roughness of less than 20 μm, in particular less than 10 μm, and / or the geometry the embossed structure of a Schleifriefen structure, in particular from parallel directed grooves corresponds.

Thus, structures are also included, which indeed have a roughness of less than 20 μπι, but not in the form of grooves, but in different geometric, preferably round or polygonal shapes are formed.

Likewise, structures are meant that, although having a geometry corresponding to a Schleifriefen structure whose roughness is at least partially greater than 20 μιη. However, a combination of both features is preferred.

In a further preferred manner, the decorative layer formed as decorative paper opposite layer arranged as a in its properties in

Substantially the decorative paper corresponding Gegenzugpapier be formed. This may cause buckling or deformation of the laminate due to different mechanical stresses can be reduced or even avoided. Preferably, the layer opposite the decorative paper is impregnated with a resin which corresponds in its tensile behavior to the resin used for the impregnation of the decorative paper, which is preferably of the same type.

The layers explained above are preferably as explained above

Paper layers, ie decorative paper, kraft paper as core layers, backing paper or overlay paper. However, the invention is not limited to the use of various layers of paper. Thus, for example, plastic layers or materials made of natural materials, preferably of wood or fabric, at least partially contribute to the construction of the laminate. In this case, a paper layer is preferably provided as the outer resinated layer of the laminate whose surface is to be used for bonding the laminate to a substrate.

As already mentioned above, one needs for the production of a

Laminate pressing means which exert a sufficient pressure and a predetermined pressing temperature on the laminate over a predetermined period of time. The above-mentioned technical problem is therefore also solved by pressing means for producing a laminate for application to a carrier material, in particular to a carrier plate, wherein a pressing surface is provided with a structure, wherein the structure substantially corresponds to a structure produced by grinding. Here, as has already been explained above, the structure used for embossing the lower layer of the laminate in depth and / or geometry corresponds to a structure produced by grinding, in particular the depth of the structure has an average roughness of less than 20 μm, in particular less than 10 μπι and / or preferably have the geometry of the structure of a Schleifriefen- structure, in particular from parallel directed grooves. The above-indicated technical problem is also solved by a method for

Production of a laminate for application on a carrier material,

in particular solved on a support plate in which a resin-impregnated

Decor layer and at least one resin-impregnated core layer are stacked on each other, in which the decorative layer and the at least one core layer are pressed together under high pressure and heat, wherein the layer arranged opposite the decorative layer is pressed and embossed with a pressing means having a structure, wherein the structure in Substantially corresponds to a structure produced by grinding.

The invention will be explained in more detail below with reference to embodiments, reference being made to the accompanying drawings. In the drawing show

1 shows a structure of a first laminate before pressing,

2 shows a structure of a first laminate before the pressing,

Fig. 3 shows a finished laminate before pressing with a support plate, Fig. 4 is a schematic representation of a belt press with a

press belt according to the invention,

Fig. 5 is a schematic representation of a cycle press with a

inventive press plate,

Fig. 6 is a schematic diagram for explaining the term contact angle, a photograph and a corresponding graphical representation of a water droplet on the surface of an inventive

Laminate in an oblique plan view, 8 shows a photograph and a corresponding diagrammatic representation of a drop of water on the surface of a device according to the invention

Laminate in a side view to determine the

Contact angle

9 is a photograph and a corresponding drawing of a

Water drop on a ground surface of a laminate [prior art] in an oblique plan view and Fig. 10 is a photograph and a corresponding drawing of a

Drop of water on a ground surface of a laminate (prior art) in a side view for determining the

Contact angle. Fig. 1 shows a laminate 2 for application to a carrier material, in particular on a carrier plate, before pressing, with a

Resin-impregnated decorative paper 4 as a decorative layer and with three resin-impregnated Kraft papers 6, 8, and 10 as core layers. The decor paper 4 and the core papers 6, 8 and 10 are suitable to be pressed together under high pressure and heat. As a result, the desired laminate 2 is produced. The decorative paper 4 has on the top of an optical pattern as a decor. Instead of the printed decorative paper 4, a plain decorative paper can be used.

According to the invention, the kraft paper 10 arranged opposite the decorative paper 4 is provided with an embossed structure during the pressing, which substantially corresponds to a structure produced by grinding. The embossed structure imparts an increased area to the surface of the layer 10, so that the bonding with a support plate is improved. FIG. 2 shows a second exemplary embodiment of a laminate 2 according to the invention before being pressed with a lowermost layer designed as a counter-tension layer 12. In this case, the backing layer 12 is provided as the lowermost layer during the compression with the embossed structure. In order to further minimize distortion of a thus constructed laminate, the backing sheet or backing paper is impregnated with a resin having a similar tensile behavior to that used to impregnate the decorative paper.

Preferably, the same resin, in particular melamine resin is used.

Fig. 3 shows a laminate 2 according to the invention in the stack with a support plate 14 made of wood material, for example. MDF board (medium density fiberboard) or HDF board (high density fiberboard) and arranged below the support plate 14 Gegenzugschicht 16. This stack is then in a press using pressure and temperature further processed to a coated wood-based panel. The embossed structure of the lowermost layer 10 or 12 corresponds in depth and / or geometry of a structure produced by grinding. It does not depend on identical geometries and / or identical topographies, ie on a true copy of a structure produced by mechanical grinding. Because the

Surface effect according to the invention is achieved when identical mechanical dimensions are maintained. Because these dimensions are largely responsible for the good adhesive properties.

Thus, for example, the depth of the embossed structure is chosen with an average roughness of less than 20 μηι, in particular less than 10 μιη, which is also produced in a typical grinding process. At the same time or alternatively, the geometry of the embossed structure corresponds to a grinding scarf structure, in particular from parallel directed scores.

An example of a structure according to the invention is given below in the form of a table, wherein the structure has been characterized with common parameters. The measurement was carried out using a surface-based method for 3D Surface measurement in accordance with EN ISO Standard 25178. In particular, the focus variation has been used as a surface-based measuring method.

Fig. 4 shows a press 20 for the production of laminates, which operates according to the CPL method. In the left-hand area of FIG. 4, a plurality of rollers 22 are illustrated, onto which the sheet-like materials of the individual layers 4, 6, 8 and 10-corresponding to the exemplary embodiment according to FIG

Laminate 2 are wound. The layers 4 to 10 are continuously unwound and fed to a pressing station 24. There, the layers 4 to 10 between two endless rotating press belts 26 and 28 are inserted and set for a predetermined by the speed of the press belts 26 and 28 period of time under high pressure. By a heating station 30, the layers are heated simultaneously with the pressurization to a high temperature. At the right end of the pressing station 24 then leaves the finished laminate as a continuous strand of the press 20th The pressing agent according to the invention for producing a laminate is in

Embodiment of FIG. 4 formed by the lower press belt 28. The

Press belt 28 has on the side facing the lower layer 10 on a previously described structure, which is impressed during the pressing operation in the pressing station 24 in the lower layer 10 of the laminate to be formed. Here, the structure of the press belt 28 substantially corresponds to a structure made by grinding, as previously explained. 5 now shows a press 40 for the production of laminates, which operates according to the HPL method. In the left-hand area of FIG. 5, a stacking device 42 is shown in which the multiple layers 4 to 10 of the laminate 2 to be formed according to the exemplary embodiment according to FIG. 2 are stacked on one another. These are tailor-made leaves, that is to say their length and width.

The staggered layers 4 to 10 of the pressing station 44 shown on the right are fed by means of a linear transport and are arranged between a lower press plate 46 and an upper press plate 48. Using a plurality of

Printing cylinders 50, the upper press plate 48 is lowered, so that the stacked layers 4 to 10 are pressed together under a high pressure. In addition, since the press plates 46 and 48 are preheated, an elevated temperature is supplied in addition to the pressure. After a predetermined period of time, the pressing station 44 is opened and the finished laminate removed. 6 shows a schematic diagram for explaining the term contact angle. On the surface of the solid is a drop of a liquid which is surrounded by a gas phase, preferably air. Due to the surface tension of the liquid on the one hand and the surface tension of the surface of the solid on the other hand, the droplet shape shown forms. At the three-phase point, ie where the solid phase, the liquid phase and the gas phase are present next to each other, the surface of the drop shape forms an angle with the surface of the Solid, which is called the contact angle. Since the surface tension of the liquid plays a role in the formation of the drop shape, the size of the area, which depends on the

Liquid is covered on the surface of the solid on. Therefore, the liquid is usually dosed so that a given area not

is exceeded. For example, when using water, an area larger than 15 mm in diameter should not be exceeded.

FIG. 7 shows a photograph and a corresponding diagrammatic illustration of a water droplet 100 on the surface of a laminate 2 according to the invention in an oblique top view. The water droplet 100 is sharply demarcated in its contour, the surrounding portions of the surface are not wetted and the underlying material of the laminate 2 has not absorbed moisture, which can be recognized by the uniform coloring of the surface.

FIG. 8 shows a photo and a corresponding diagrammatic illustration of a water droplet 100 on the surface of a laminate 2 according to the invention in a side view for determining the contact angle. For example, drop shape analysis (DSA) can be used to determine the contact angle. The drop contour analysis is an image analysis method for determining the contact angle from the side view or from the shadow image of a lying drop on the surface. For this purpose, a drop is dosed onto a solid surface (lying drop). With the help of a camera, a picture of the drop is taken.

For a rough, usually sufficient analysis, the angle between the liquid surface and the surface of the laminate can be determined directly with a ruler. In the present case, the contact angle to 50 ° was determined in this way in Fig. 8 with the aid of a ruler. For a more detailed analysis, the image can be transferred to drop contour analysis software. On the basis of a grayscale analysis of the image, a contour recognition is first performed. In the second step, a geometrical model describing the drop contour is fitted to the contour using a mathematical method. The contact angle then results from the angle between the determined drop contour function and the sample surface whose projection in the drop pattern is referred to as the baseline.

Fig. 9 shows a photograph and a corresponding drawing of a

Drop of water 100 on a ground surface of a laminate 102 in an oblique plan view, ie on a sample, as known from the prior art. In contrast to FIG. 7, the resting drop 100 can no longer be sharply delimited and the drop 100 has a flatter shape than shown in FIG. In addition, the portions 100 surrounding the droplets 100 of the surface have become moist in that a portion of the water of the droplet 100 from the

Laminate has been added. The wetness shows through the dark

Discoloration compared to the much brighter wider environment of the surface.

In Fig. 10 is a photograph and a corresponding drawing of a water droplet on a ground surface of a laminate 102 in a side view for determining the contact angle. As is apparent from Fig. 9, the drop 100 has a flatter shape and the contact angle was determined in the photograph with a ruler at 10 °. For the experiments shown in FIGS. 7 to 10, tap water having the following physical and chemical properties was used:

- water temperature 20 ° C (room temperature)

- pH 7.5

- Electrical conductivity at 25 ° C: 709

- carbonate hardness: 11.0 ° dH

- Total hardness: 13.4 ° dH with an alkaline earth sum of 2.4 mmol / l - Nitrate NO3-: 12 mg / l

- Nitrite NO2-: <0.02 mg / 1

- Total phosphate: P0 ₄ ^{3 "} : 1.2 mg / 1

- Silica Si0 ₂ : 8.8 mg / 1

Fluoride P: 0.13 mg / l

- Chloride Ch 74 mg / 1

Sulfate SO4 ² -: 59 mg / l

Bicarbonate HCO3 ^" : 213 mg / 1 mg / l

- sodium Na ⁺ : 35 mg / l

Magnesium Mg ²⁺ : 11 mg / l

Calcium Ca ²⁺ : 79 mg / l

- potassium K ⁺ : 4 mg / 1

The drop size was metered so that the drop had an area with a diameter of about 10 to 15 mm, in the ground laminates according to FIGS. 9 and 10 at the beginning before deliquescence.

Claims

P a n t a n s p r e c h e

Laminate for application to a carrier material, in particular to a carrier plate,

with a resin impregnated decorative layer (4) and

with at least one resin-impregnated core layer (6, 8, 10),

wherein the decorative layer (4) and the at least one core layer (6, 8, 10) are suitable for being pressed together under high pressure and heat,

characterized,

in that the layer arranged opposite the decorative layer is provided with an embossed structure which essentially corresponds to a structure produced by grinding.

Laminate according to claim 1,

characterized,

a drop of tap water at room temperature with a maximum diameter of 15 mm with the layer having the embossed structure assumes a contact angle above 40 °, in particular above 50 °.

Laminate according to claim 1 or 2,

characterized,

that the embossed structure in depth and / or geometry corresponds to a structure produced by grinding.

Laminate according to one of claims 1 to 3,

characterized,

that the depth of the embossed structure has an average roughness of less than 20 μιτι, in particular less than 10 μπι. Laminate according to one of claims 1 to 4,

characterized,

that the geometry of the embossed structure corresponds to a grinding scarf structure, in particular from parallel directed scores.

Laminate according to one of claims 1 to 5,

characterized,

in that the layer (10, 12) arranged opposite the decor layer (4) designed as decor paper is designed as a counter-tension paper substantially corresponding in its properties to the decorative paper.

Laminate according to claim 6,

characterized,

that the layer opposite the decor paper is impregnated with a resin which corresponds in its tensile behavior to the resin used for the impregnation of the decorative paper, which is preferably of the same type.

Pressing means for producing a laminate for application to a

Carrier material, in particular a carrier plate,

with a pressing surface with a structure,

wherein the structure substantially corresponds to a structure made by grinding.

Pressing means according to claim 8,

characterized,

that the structure is in depth and / or geometry by grinding

produced structure corresponds.

10. pressing means according to claim 8 or 9,

characterized,

that the depth of the structure has an average roughness of less than 20 μιτι, in particular less than 10 μηι.

Pressing means according to one of claims 8 to 10,

characterized,

in that the geometry of the structure has a grinding-scarf structure, in particular parallel-directed scores.

12. A process for producing a laminate for application to a

Carrier material, in particular a carrier plate,

in which a resin-impregnated decorative layer and with at least one resin-impregnated core layer are stacked on top of each other,

in which the decorative layer and the at least one core layer are pressed together under high pressure and heat,

characterized,

in that the layer arranged opposite the decorative layer is pressed and embossed with a pressing means having a structure, the structure substantially corresponding to a structure produced by grinding.